"Companies whose global profits total $125bn (£86.7bn) cannot credibly claim that they are unable to check where key minerals in their productions come from"

In a report into cobalt mining in the Democratic Republic of the Congo, it found children as young as seven working in dangerous conditions. Cobalt is a a vital component of lithium-ion batteries.

The firms said that they had a zero tolerance policy towards child labour.

The DRC produces at least 50% of the world's cobalt. Miners working in the area face long-term health problems and the risk of fatal accidents, according to Amnesty.

It claimed that at least 80 miners had died underground in southern DRC between September 2014 and December 2015.

It also collected the testimonies of children who allegedly work in the mines.

Paul, a 14-year-old orphan, started mining when he was 12 and told researchers: "I would spend 24 hours down in the tunnels. I arrived in the morning and would leave the following morning ... I had to relieve myself down in the tunnels … My foster mother planned to send me to school, but my foster father was against it, he exploited me by making me work in the mine."

UNICEF estimates that there are approximately 40,000 children working in mines across southern DRC.

In response to the report, Apple said: "Underage labour is never tolerated in our supply chain and we are proud to have led the industry in pioneering new safeguards."

It said that it conducts rigorous audits on its supply chain and any supplier found hiring underage workers is forced to:fund the worker's safe return home, finance the worker's education at a school chosen by the worker or his/her family, continue to pay the worker's wages, offer him or her a job when he or she reaches legal age to work.

On cobalt specifically it added: "We are currently evaluating dozens of different materials, including cobalt, in order to identify labour and environmental risks as well as opportunities for Apple to bring about effective, scalable and sustainable change."

Samsung said that it had a "zero tolerance policy" towards child labour and that, it too, conducted regular and rigorous audits of its supply chain.

"If a violation of child labour is found, contracts with suppliers who use child labour will be immediately terminated," it said.

Sony commented: "We are working with the suppliers to address issues related to human rights and labour conditions at the production sites, as well as in the procurement of minerals and other raw materials."

With the 2014 World Cup in Brazil now less than 30 days away, eight workers have died building stadiums for the event. Even one death is a steep price for any sporting event, and this is a black eye for Brazil, which is behind schedule in its preparation. There is also some precedent: Two workers died during construction for the 2010 World Cup in South Africa. Yet the losses in Brazil and South Africa look minuscule compared with the crisis mounting in Qatar, which is scheduled to host the World Cup in the summer of 2022, despite extremely hot weather. Deaths there could number in the thousands.

In a new segment from ESPN’s (DIS) investigative wing, E:60, reporter Jeremy Schaap travels to Qatar to see the housing where Qatar’s immigrant workers live. The conditions are filthy, cramped, and dangerous. Even without the pressure of the spotlight of the World Cup, hundreds of young men die every year from accidents, suicides, and heart attacks—their bodies shipped back to widows and orphaned children in Nepal, India, Pakistan, the Philippines, and other countries that send workers to the tiny emirate.

The bedroom of workers' accommodation in the Industrial Area of Doha

Qatar employs a Kafala labor system, which effectively controls the lives of its foreign workers, who make up the majority of the population. (Only about 250,000 of Qatar’s 2 million residents are citizens.) Workers take out loans from “sponsor” companies to cover the cost of travel and housing. These sponsors then control everything about the workers’ lives in Qatar, including the right to leave. As it stands, Kafala will supply the labor force to build either eight or 12 stadiums for the 2022 World Cup.

The Qatar organizing committee reported yesterday that no workers had died building World Cup venues, mostly because construction has not yet begun in earnest. According to the E:60 segment, 184 Nepali workers in Qatar have died in the past year and 680 in the past five years. Currently, 400,000 Nepali workers are in the country. India reports 450 deaths from its emigrants to Qatar in 2012 and 2013. Sharan Burrow, the general secretary of the International Trade Union Confederation (ITUC), tells Schaap that under the current system more than 4,000 workers will die during World Cup construction, a total she calls “insanely criminal.”

Under pressure from ITUC and other human rights organizations, Qatar announced today that it will amend its labor laws and remove employers’ control over their employees’ exits from the country. It remains to be seen whether the new measures will bring significant change. Burrow calls previous reforms “sham provisions” that rely on self-audits by employers. Nothing short of abolishing Kafala will do. And Burrow contends that Qatar would do it if FIFA President Sepp Blatter made it the price of hosting the World Cup.

If Santa had a track record in paying his temporary elves the minimum wage while pushing them to the limits of the EU working time directive, and sacking them if they take three sick breaks in any three-month period, this would be an apt comparison. It is probably reasonable to assume that tax avoidance is not "constitutionally" a part of the Santa business model as Brad Stone, the author of a new book on Amazon,The Everything Store: Jeff Bezos and the Age of Amazon.

In the wake of the BBC documentary, Hywel Francis, the MP for Aberavon, managed to get a meeting last week with Amazon's director of public policy, a meeting he's been trying to get for years. He's reluctant to speak about the complaints he's heard from his constituents but says that "the plant is exceptional in the local area in having no union representation. It's been a long haul to even get in there and find out what is going on." It's been a black hole where the lack of any checks upon its power has left a sense that everything is pared to the absolute bone – from the cheapest of the cheap plastic safety boots, which most long-term employees seem to spend their own money replacing with something they can walk in, to the sack-you-if-you're-sick policy, to the 15-minute break that starts wherever you happen to be in the warehouse.

We want cheap stuff. And we want to order it from our armchairs. And we want it to be delivered to our doors. And it's Amazon that has worked out how to do this. Amazon isn't responsible for the wider economy, but it's the wider economy that makes the Amazon model so chilling. It's not just the nicey nice jobs that are becoming endangered, such as working in a bookshop, as Hugh Grant did in Notting Hill, or a record store, as the hero did in Nick Hornby's High Fidelity, or the jobs that have gone at Borders and Woolworths and Jessops and HMV, it's pretty much everything else too. Next in line is everything: working in the shoe department at John Lewis, or behind the tills at Tesco, or doing their HR, or auditing their accounts, or building their websites, or writing their corporate magazines.

World trade has been the engine of world economic growth in the last 50 years. But many poor countries have been left behind as rich countries have subsidised agriculture and blocked access to their markets.

BBC News Online looks at how poor countries have fared as trade has increased.